Stabilized dry rosin size



Patented Sept. 1, 1942 Hercules 14:: on, 33 5,, assign? ttilzr v. u\ a corporation oi illieiaware a any aosm sizn L on,

No lilira. Application December 1M0,

' Senim No. 368,.d55

8 (Claims.

This invention relates to an improvement in -osin size and in particular concerns saponiied rosin size compositions stabilized against atnospheric oxidation.

As is well known, rosin size may be prepared and utilized either in dry form or as a liquid or aaste in admixture with water. The dry iorm, iowever, is in general deemed the most satisfac- ;ory because of its ease and economy of shipnent, the type of dry rosin size prepared by spray-drying saponified or partially saponified rosin being especially desirable because of its low iensity and high rate of solution in water.

The dry forms of rosin size, particularly the zype formed by spray-drying, however, are disadvantageous inthat they have a strong tendency to oxidize and spontaneously decompose in the presence of air. Where, as is not uncommon, some free rosin is contained in the size, there is even a greater tendency to oxidize. Such oxidation, and consequent heating, is not only highly deleterious to the size itself but presents a considerable fire hazard during storage and shipment.

I have now found that dry rosin sizes comprising saponified rosin or saponified abietic acid may be effectively stabilized against oxidation by the addition of a small proportion of certain N-alkylsubstituted beta-naphthylamines which act as anti-oxidants. Dry rosin sizes stabilized in this manner may be stored for long periods of time without danger of decomposition by oxidation or spontaneous combustion.

The N-alkyl-substituted beta-naphthylamines which may be employed as anti-oxidants in preparing stabilized dry rosin size compositions according to the invention have the general formula RI Rat wherein R represents a lower alkyl radical, i. e. an alkyl radical containing less than flve carbon atoms, and R represents a lower alkyl radical or hydrogen. Examples of such compounds are N-methyl-beta-naphthylamine, N-ethyl-betanaphthylamine, N,N'-diethyl-beta-naphthylamine, N-isopropyl-beta-naphthylamine, N,N'-din-butyl-beta-naphthylamine, etc.

The proportion of anti-oxidant employed in preparing the stabilized dry size compositions of the invention depends upon a number of factors, among which are the particular anti-oxidant used a size is considered suficiently stabilized for all ordinary purposes if it resists oxidation for about 48 hours when subjected to an accelerated oxidation treatment known as the Mackay test. The treatment consists in placing a sample of the stabilized size in a wire basket suspended in a water-jacketed chamber maintained at a tern-- perature of 100 C. A small volume of air is passed continuously through the chamber for the desired length of time, during which time the tem= perature of the sample-which is a measure of the oxidation, is accurately determined. Dry rosin size containing no anti-oxidant will oxidize to a considerable extent, i. e.-its temperature will rise considerably above 100 C., and it may even ig= nite and burn when subjected to this test over a period of about 48 hours, while a size stabilized according to the invention will undergo substantially no oxidation.

The optimum proportion of anti-oxidant also depends upon the composition of the size itself, a somewhat larger proportion being required for sizes containing free alkali or free rosin. Thus, for example, a neutral saponified rosin size may be rendered stable to oxidation as determined by the 48-hour Mackay test by the addition of about 0.3 per cent of N-ethyl-beta-naphthylamine, whereas a size containing 0.5 per cent free alkali may require the addition of 0.5-0.8 per cent oi N-ethyl-beta-naphthylamine to secure such a degree of stabilization. Similarly, a size containing 5.0 per cent of free rosin may require the use of 1.0 per cent by weight of the anti-oxidant to secure good stabilization. The type of dry size. i. e. whether it has been prepared from wood rosin, gum rosin, or rosin which has been heattreated to efiect partial decarboxylation, is also of influence on the proportion of anti-oxidant to be used. Thus, sizes comprising saponified rosin usually require asomewhat larger propontion of the anti-oxidant than do the other types. In general, however, it will be found that from about 0.1 to about 1.5 per cent of the anti-oxidant, based on the weight of the rosin used in preparing the size, will be sufllcient to render any dry size however, the anti-oxidant will desirably and most efiectively be added to the ,size during its preparation by the saponiflcation of rosin. Aparand the degree of stabilization desired. Usually ticularly convenient mode of effecting such ad 5.0 per cent free rosin, either before or'during the saponification reaction. Upon completion of the reaction, the mixture may be desiccated by spray or drum drying to produce a dry size having the anti-oxidant uniformly distributed there-' The following table presents comparative data 7 illustrative of the degree of stabilization secured by the use of several of the anti-oxidants or the present class, In each experiment, approximately 40 parts of gum rosin was'saponined with 5 parts of sodium hydroxide in the form or a 39 percent aqueous solution. When the sap'oniilcation reaction was about one-half completed,

the anti-oxidant, in the proportion given in the table and dissolved in paraflln oil, was added to the reaction-mixture. Upon completion of the reaction, the mixture was spray-dried to form a dry powder having th anti-oxidant uniformly distributed throughout. A sample of each of the compositions so prepared was then tested for ease of oxidation by the 48-hour Mackay test, and the composition stabilized with N-methylbeta-naphthylamine was subjected to a standard oxygen demand test in an oxygen absorption train. The oxygen demand is expressed as the per cent by weight oxygen absorbed over a fourhour period.

Table E m Anti-oxidant o P E No. demand Mackay test Name Percent 1 None (control) s. 19 Burned in 13 hrs. 2 N methyl beta 0. 5 l. 09 Stable.

naphthylamine. 3 Nghethyl-beta-naph- 0. 5 Do.

y e. 4 N,N diethyl beta 0. 5 Do.

nsphthylamine.

Other modes or applying the principle of my invention may be employed instead of those explained, change being made as regards the materlals employed, provided the ingredients stated a by any of the appended claims or the equivalent of such. stated ingredients be employed.

What I claim and desire to protect by Letters Patent is:

1. A stabilized dry size composition comprising saponifled rosin and,.as an anti-oxidant thereior, a beta-naphthylamine derivative having the general formula wherein R represents a lower alkyl radical and R represents a substituent selected from the class consisting of hydrogen and lower alkyl radicals, said beta-naphthylamine derivative being present in an amount sufilcient to render the composition substantially resistant to oxidation.

2. A stabilized dry size composition comprising saponified rosin, free rosin, and, as an anti-oxidant therefor, a beta-naphthylamine derivative havingthe generaliormula Z wherein R represents a lower alkyl radical and R represents a substituent selected from the class consisting of hydrogen and lower alkyl radicals; said beta-naphthylamine derivative being present in an amount sufiicient to render the composition substantially resistant to oxidation.

3. A stabilized dry size composition comprising saponified rosin and, as an anti-oxidant therefor, N-methyl-beta-naphthylamine in an amount sufficient to render the composition substantially resistant to oxidation.

4. A stabilized dry size composition comprising saponifled rosin, free rosin, and, a an, anti-oxidant therefore, N-methyl-beta,naphthylamine in an amount suflicient to render the composition substantially resistant to oxidation.

5. A stabilized dry size composition'comprising saponified rosin and, as an anti-oxidant therefor, N-ethyl-beta-naphthylamine in an amount suflicient to render the composition substantially resistant to oxidation.

6. A stabilized dry size composition comprising saponified rosin, free rosin, and, as an anti-oxidant therefor, N-ethyl-beta-naphthylamine in an amount suflicient to render the composition substantially resistant to oxidation.

7. A stabilized dry size composition comprising saponified rosin and, as an anti-oxidant therefore, N,N'-diethylbeta-naphthylamine in an amount sufllcient to render the composition substantially resistant to oxidation.

8. A stabilized dry size composition comprising saponiiied rosin, free rosin, and, as an anti-oxidant therefor, N,N'-diethyl-beta-naphthylamine in an amount suiiicient to render the composition substantially resistant to oxidation,

ARTHUR C. DRESHFIELD. 

